This is a wide shot of the full sewing frame, sometimes called the "sewing table" or "sewing press" (Zaehnsdorf 20). To be considered a full sewing frame, it must contain a bed, two screws, a beam/crossbar, and threads (20). The threads on the crossbar are called lay cords (20). The pieces of wood underneath the crossbar are called nuts, which help tighten the bar height and keep it in place (Hasluck 42).

The amount of fastened lay cords are usually five (Hasluck 20), but it is possible to successfully sew a book with a frame with no less than three cords, usually for smaller books up to 6 by 9 inches in size (Banister 80). This can be seen in the picture, as there are only three lay cords.

In bookbinding, the sewing frame is used after the pages of the book has been beaten and collated, which is to make the pages lie close together so it can be bound; this is so it can be sown on as if it were one solid object rather than multiple (Hasluck 38). After it is collated, the spine of the pages are moved to touch the lay cords and enter their saw channels—created if kettle-stitching—and are sewn onto with the help of the sewing frame (41).

Additionally, it is possible to sew more than one book at a time using the sewing frame (46). As long as the books are of similar sizes, the sewer can sew them all and keep their binds separate as long as the lay cords are kept long enough to cut and leave 2.54cm between each book (47).

This is a close-up of the lay cords on the crossbar. These lay cords are acting as sewing supports.

When setting up lay cords, it is best to make the cords all the same size (Banister 81). That way, when strung up on the crossbar, they all get the same amount of tension; the sewing frame is meant to control the tension of sewing supports and keep them all of similar tension (Conroy 19).  Ultimately, tension is the important part of bookbind sewing, and is the reason books being sewn off frame were becoming concave; if the cords are strung up too tight on the sewing frame, the spine on the book will become concave from the pull (19), but tension too loose will result in a spine that moves around too much, resulting in a flabby spine and a low quality bind (19). For example, a bind with excessive tension on the supports will produce a book unable to close properly without the use of clasps (21). Additionally, finely adjusting the tensions of the support in post is impossible, and sewing off the sewing frame will "normally cause cranky action and premature breakdown" (20) because of inconsistent tension (20).

The ideal way to string up lay cords is to screw them up tightly, but loose enough to allow them to move freely backwards or forwards (Zaehnsorf 21). 

There are ways to fix a flabby spine (21), and certain types of sewing will try and disguise uneven tension of supports (20), but a fix can be avoided entirely by getting the correct tension for a quality bind via the sewing frame. The problems of bookbinding prior to sewing supports and the sewing frame (Szirmai 95) can still be achieved when the tools are not used correctly.

This photo shows a lay cord off of the crossbar with its key tied to it, which is the metal in this image. Keys can be made of brass, copper, aluminium, or hardwood (Banister 80) and are 0.15cm in height (81). The keys are virtually invisible when looking at the frame from a full angle, as shown in the image prior, but that is because they are snugly placed at the bottom of the sewing frame bed when in use. The lay cord is tied to the key by twisting the end of it around the key twice, an then sewing a half hitch onto it (Zaehnsdorf 21). These keys are essential to keep the lay cords tight onto the sewing frame and keep their tension (Banister 80), which mentioned previously, is the most important part of the sewing supports.

Lay cords were usually made of alum-tawed skin, and this material for supports were preferred in Europe in the 16th century (Miller 393). However, many different materials were used for lay cords, which all have a different stiffness and different thicknesses (Conroy 15), which makes a difference in binding since these materials might differ in stretchiness (15). For example, tawed pig skin is more pliable and durable than cord, but tawed skin pliability differs depending on the animal and the age of that animal (15). Additionally, silk can also be used (Zaehnsdorf 23).

Furthermore, bookbinding tape can be used on a sewing frame in a similar fashion to cords; bookbinding tape also has its own key, called the tape key (Banister 59).

This is a close up of the parts of the screw. The crossbar has a hole to attach to the screw, but the wooden plank underneath the crossbar, the nut, is what is screwable (Hasluck 42). When setting up the sewing frame for use, the screws of the frame have to be screwed up to ensure the proper height of the thread an also make sure that the lay cords become taut (42). They are then tightened to make sure that they do not give when the cords are being stretched (42), because if they were to give, the threads would lose their tension and ruin the quality of the sew.

The screws allow for the height to be adjustable, which can be helpful when sewing more than one book at a time; its a time saver to sew as many books as the sewing frame can hold (Hasluck 42).

When the bookblock is fully sewn, the nuts get slackened so that the lay cords can be detached from the keys and the bar (Zaehnsdorf 24). Sometimes, when the bar is dropped or slackened, if the tension on the cords were too tight, the threads on the bookblock will contract and cause a concave spine (19).